Medicinal syringe



Dec. 16, 1958 A. R. MlzzY MEDICINAL sYRINGE:

Filed July 2a, 1954 United States Patent O MEDICINAL SYRINGE Arnold Robert Mizzy, New York, N. Y.

Application July 28, 1954, Serial No. 446,367

2 Claims. (Cl. 128-220) This invention relates to the art of syringes for injection of medicinal fluids into the body tissue.

It is among the objects of the invention to provide a disposable syringe of the above type which is neat, compact, light in weight and has but few parts which may readily be fabricated and assembled at low cost, which is simple to operate, requiring but a single manipulation to apply it to the patient to insert the needle and to eject the medicinal fluid therefrom, which may readily be charged with a predetermined volume of medicinal fluid, and insures sterility of all of the parts of the device which enter the body tissue or are adjacent the region of application of the needle so that it is ready for use without further sterilization.

Another object is to provide a syringe of the above type which provides a dependable safeguard against exposure of the contents of the syringe to the atmosphere and against coagulation of the fluid in the needle, thereby dispensing with the need for preliminary ejection of lluid from the needle `before use with resultant waste.

Another object is to provide a syringe of the above type which provides a dependable seal between the con tents of the unit and the atmosphere to prevent leakage regardless of extreme temperature changes.

According to the invention, these objects are accomplished by the arrangement and combination of elements hereinafter described and particularly recited in the claims.

ln the accompanying drawings in which are shown one or more of various possible embodiments of the several features of the invention,

Fig. 1 is a longitudinal sectional view of one embodiment of the invention,

Fig. 2 is a transverse sectional view taken along line 2-2 of Fig. l,

Fig. 3 is a view similar to Fig. 1 of another embodiment thereof,

Fig. 4 is a transverse sectional view taken along line 4-4 of Fig. 3,

Fig. 5 is a fragmentary view similar to Fig. 3 with the rear end of the needle in operating position,

Fig. 6 is a fragmentary perspective view of the reduced end of the plunger of Fig. 4,

Fig. 7 is a longituidnal fragmentary sectional view of still another embodiment, and

Fig. 8 is a view taken along line 8--8 of Fig. 7.

Referring now to the drawings, the syringe shown in Fig. 1 comprises a tubular barrel 1l, preferably of plastic, closed at one end as at 12`and open at its mouth as at 13.

Slidably mounted in barrel 11 is a plunger 14 also preferably of plastic, and of length desirably greater than that of the barrel. Extending longitudinallyvthrough the plunger and axially aligned therewith is a hollow injection needle 15, the rear end 16 of which is positioned in an axial recess 17 at the inner end 18 of the plunger.

Although the needle may be mounted in the plunger v2,864,364 Patented Dec. 16, 1958 14 in any suitable manner, it desirably is molded integrally therewith so that it is securely retained therein without likelihood of displacement when pressure is applied against the needle in use of the syringe.

The plunger 14 adjacent its rear end 16 has an annular periphreal groove 19 in which is positioned a resilient seal 21, preferably an 0 ring of natural or synthetic rubber, which forms a liquid and pressure tight seal of relatively narrow width, between the exterior of the unit and a variable volume chamber 22 formed between the closed end-12 of the barrel and the inner end 18 of the plunger.

The outer end 23 of the plunger from which protrudes the pointed end 24 of the needle is desirably rounded as at 25, and a peripheral annular groove 26 is provided adjacent said rounded end.

To insure the sterility of the needle and the end 25 of the plunger which contacts the skin of the patient adjacent the point of insertion of the needle, means are provided to cover the pointed end 24 of the needle, as well as the rounded end 25 of the plunger.

Such means desirably comprises a hollow cap 28 of resilient material such as rubber. The mouth 29 of the cap has an inturned annular flange 31 of diameter slightly less than the diameter of the end 23 of the plunger. Thus when the cap 28 is fitted over the end 23 of the plunger, the ange 31 will snap into annular groove 26, securely yet removably to retain the cap in position and effectively sealing the needle and the rounded end 25 of the plunger from contamination.

Inasmuch as uid in chamber 22 may ow through the ice . lhollow needle 15, to further insure that no air will reach the pointed end 25 of the needle and also to insure that there will be no leakage, the hollow cap 28 is so designed that when it is positioned on the end 23 of the plunger 14, the pointed end 24 of the needle will be embedded in the material of the cap axially aligned with the recess 32 therein as at 33 to provide a highly effective seal that permits substantially no air to leak to the needle.

To charge the unit, the barrel 11 is lilled with a predetermined quantity of fluid and with the cap 28 preferably mounted thereon, the plunger 14 is placed into the barrel so that the end 18 of the plunger is adjacent the mouth 13 of the barrel.

To use the syringe, it is merely necessary to remove the cap 28, place the point of the needle at the desired position against the body of the patient and then force the needle into the body tissue until the rounded portion 25 of the plunger abuts against the skin of the patient. With continued pressure on the barrel, the pressure against the lluid in chamber 22 and against the inner side of the O ring will increase and will be greater than the pressure on the outer side of the O ring which is exposed to atmosphere. Thus the 0 ring will be forced into the space between the plunger and the inner surface of the barrel to provide a dependable sliding seal and all of the lluid in chamber 22 will be forced through the needle into the body tissue of the patient.

Where absolute security is required against exposure to the air, of the contents of the chamber 22, such as might occur with even slight leakage of such air past the cap 28, the embodiment shown in Fig. 3 is provided.

In this embodiment which is similar to the embodiment of Fig. 1, corresponding elements have the same reference numerals primed.

The end 18' of the plunger 14', instead of the annular groove 19 and recess 17, has a cylindrical axial extension 36 of reduced diameter with an annular flange 37 at its end having a plurality of longitudinal notches 38 therein and the rear end 16' of the needle 15' extends beyond such ange end and also is pointed as at 39.

Positioned on extension 36 is a sealing member 41, desirably a cylindrical plug of resilient material, such as natural or synthetic rubber. As is clearly shown in Fig. 3, the plug 41 has an outer diameter slightly greater than the inner diameter of the barrel 11 and -has a plurality of annular grooves 42 in its outer periphery, i1- lustratively two in number, delning three annular ridges 43, 44 and 45 which serve as seals in the same manner as the ring 21.

The plug (41 has a cylindrical recess 46 in one end of diameter slightly less than the diameter of ange 37 and which occupies a major portion of the length of the plug and a relatively shallow recess 47 at its other end, the wall between said recess delining a partition 48.

The recess 46 has` at least two spaced annular grooves 49 and 51 in its inner periphery and when the ange end 37 of the plungei' 14' is positioned in groove 49, the pointed end 39 of the needle will be spaced from the partition 48.

Thus when the plunger 14' with its plug 41 thereon is positioned in the barrel 11 near its mouth 13', the ridges 43, 44 and 45 will provide a dependable seal between the adjacent surfaces of the barrel and the plunger and the partition 48 will prevent leakage of iluid from chamber 22 into the needle. The end 23' of the plunger 14 may have a cap 28 mounted thereon in the same manner as the cap 28 of the embodiment of Fig. 1. Thus absolute security against leakage of fluid into the needle is provided with complete safeguard against contamination or coagulation of such fluid.

In use of the syringe shown in Fig. 3, the cap 28' is removed from the end of the plunger 14' and the user readies the syringe for operation by pushing the plunger 14 into the barrel 11. As the tluid in chamber 22' is precluded from escaping therefrom by the plug 41, it will form a substantially rigid body which will prevent inward movement of plug 41.

As a result, the llange 37 at the end of the plunger will cam over the ridge 53 (Fig. 5) between grooves 49 and 51 and snap into groove 51 and the end 39 of the needle will pierce partition 48 to provide communication between the tluid in chamber 22' and the bore of needle The notches 38 in llange 37 permit air to escape past the llange so that it may move freely from groove 49 to groove 51.

The needle 15' may then be inserted into the body tissue as previously described with the end 25' of plunger 14' abutting against the skin of the patient and the barrel 11 pressed down onto the plunger. As a result, plunger 14 and plug 41 will move into the barrel 11' so that the duid in chamber 22', will be ejected through the needle.

By reason of the ridges 43, 44 and 45, which function as 0 rings and the greater pressure on the uuid in the chamber than the atmospheric pressure, when the barrel is pressed, the ridges will be forced outwardly to wedge between the adjacent sm'faces of the plunger and the barrel to provide a dependable sliding seal which will prevent any leakage.

Where it is desired to provide a syringe that can be` subjected to extreme conditions of heat and cold without likelihood of leakage of the tluid from the barrel chamber, the O ring 2l and associated groove 19 in the embodiment of Fig. l can be eliminated and the sealing plug 55 shown in Figs. 7 and 8 is provided.

As is clearly shown in Figs. 7 and 8,l the sealing plug 55 is a circular member of resilient compressible material such as natural or synthetic rubber. The plug 55 has an axial bore 56 through which the end 16" of the needle 15" extends, the bore being of enlarged diameter at its outer end defining a recess 17". The diameter of plug 55 at its end 57 is substantially the same as the diameter of the adjacent end 18" of the plunger 14" and the surfaces 58, 59 of the plug and the plunger are positioned against each other. As the diameter 0f bor? 59 i8 slightly 4 less than the diameter of needle 15", when the end 16" of the latter is forced through bore 56, the plug will be securely retained on end 16" of the needle against the end 18" of the plunger. If desired, a suitable bonding cement may also be used to retain the plug and the plunger together.

As is shown in Figs. 7 and 8, the plug 55 has an annular groove 61 coaxial with the needle 15" and tapered inwardly so that the width of the groove is greatest at its outer end as at 62. The side wall 63 of the plug tlares outwardly from near the end 57 thereof so that the diameter of the outer end 64 of the plug is greater than that of the barrel into which it is to be inserted.

To position the plunger 14" and plug 55 thereon into the barrel, it is merely necessary to compress the outer end 64 of the plug to reduce its diameter so that it will tt into the barrel and the groove 61 facilitates such compression of the plug.

With the plug and plunger in the barrel, by reason of the tendency of the outer end 64 of the plug to move outwardly it will press snugly against the inner surface of the barrel providing a dependable leal.

In the event that the barrel should contract with extreme cold, the end 64 of the plug will move laterally inward with ease, due to the annular groove 61 and hence no injury will be caused to the barrel or the plug by reason of such contraction. If the barrel should expand with extreme heat, the tendency of the end 64 of the plug to move laterally outward will retain the latter snugly against the inner surface of the barrel so that a dependable seal will be maintained.

As the operation of the syringe shown in Figs. 7 and 8 is substantially identical to that shown in Fig. l, no further description of such operation will be given.

By reason of the simplicity of the syringes above described, they may be used by even an unskilled patient with a minimum of instruction and insure dependable vsafeguard against exposure of the lluid contents thereof to the atmosphere. The syringe shown in Figs. 3 to 6 prevents coagulation of the uid therein, as a barrier is provided until the syringe is ready for use and in the embodiment of the syringe shown in Figs. 7 and 8 safeguard against leakage of tluid from the barrel is provided even with extreme temperature variation. As the syringes may readily be fabricated by mass production methods from low cost materials, they can be discarded after use, thereby eliminating the need for sterilization and refilling.

As many changes could be made in the above construction and many apparently widely different embodiments of this invention could be made without depart ing from the scope of the claims, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

Having thus described my invention, what I claim as new and desire to secure by Letters Patents of the United States is:

l. An injection syringe comprising an elongated barrel, a plunger slidably mounted in the barrel and dening a variable volume chamber with respect thereto to contain a charge of medicinal fluid, said plunger having a hollow needle retained therein, extending longitudinally thereof and protruding at its pointed end beyond the front end of said plunger, a resilient member on said plunger adjacent the rear end thereof and coacting with the inner wall of said barrel to provide a seal to prevent leakage of uid from said chamber, said plunger having an annular peripheral groove near its front end, a cap of resilient material having a recess therein with an inturned flange at its mouth of inner diameter slightly less than the diameter of the front end of said plunger so that said ange will snap into said peripheral groove removably to retain said cap on the front end of said plunger, said cap having a mass of solid material axially aligned with the recess and into which the pointed end of the needl is embedded.

2. An injection syringe comprising an elongated barrel, a plunger slidably mounted in said barrel and defining a variable volume chamber with respect thereto to contain a charge of medicinal uid, said plunger having a hollow needle retained therein, extending longitudinally thereof and protruding beyond both ends thereof, both of the protruding ends of the needle being pointed, said plunger having a reduced diameter axial extension at its rear end from which the rear pointed end of the needle protrudes, said extension having an annular flange at its free end with a longitudinal groove in its periphery, a resilient sealing member mounted on the rear end of the plunger and coacting with the inner wall of said barrel to provide Va seal to prevent leakage of uid from said chamber, said sealing member comprising a plug having a recess therein with at least two spaced internal annular grooves, said recess having a wall at one end, said flange normally being positioned in the annular groove remote from the wall at the end of the recess and movable into References Cited in the le of this patent UNITED STATES PATENTS 2,478,844 Smith Aug. 9, 1949 2,490,447 Lockhart Dec. 6, 1949 2,490,551 Smith Dec. 6, 1949 2,495,027 Smith Jan. 17, 1950 2,497,562 Smith Feb. 14, 1950 2,539,510 Friden Jan. 30, 1951 2,578,813 Kollsman Dec. 18, 1951 2,708,438 Cohen May 17, 1955 

